refactor(internal/repometadata): use library to generate metadata (#4068)

Refactor library struct as one of the inputs to generate metadata from
API.

In Go clients, some metadata, e.g., documentation url and distribution
name, requires Go specific configuration from the library.

This is a preparation step for Go metadata generation.

For #3617

Author: JoeWang1127

internal/repometadata/repometadata.go

@@ -33,16 +33,6 @@ var (
 	errNoServiceConfig = errors.New("library has no service config from which to get metadata")
 )
 
-// LibraryInfo contains information about a library that is not available in the service config.
-type LibraryInfo struct {
-	// DescriptionOverride overrides the library description from the service config.
-	DescriptionOverride string
-	// Name is the name of the library distribution package.
-	Name string
-	// ReleaseLevel is the release level (e.g., "stable", "preview").
-	ReleaseLevel string
-}
-
 // RepoMetadata represents the .repo-metadata.json file structure.
 type RepoMetadata struct {
 	// APIDescription is the description of the API.
@@ -105,36 +95,31 @@ func FromLibrary(library *config.Library, language, repo, googleapisDir, default
 	if api.ServiceConfig == "" {
 		return fmt.Errorf("failed to generate metadata for %s: %w", library.Name, errNoServiceConfig)
 	}
-	info := &LibraryInfo{
-		DescriptionOverride: library.DescriptionOverride,
-		Name:                library.Name,
-		ReleaseLevel:        library.ReleaseLevel,
-	}
-	return FromAPI(api, info, language, repo, defaultVersion, outdir)
+	return FromAPI(api, library, language, repo, defaultVersion, outdir)
 }
 
-// FromAPI generates the .repo-metadata.json file from a serviceconfig.API and additional library information.
-func FromAPI(api *serviceconfig.API, info *LibraryInfo, language, repo, defaultVersion, outputDir string) error {
+// FromAPI generates the .repo-metadata.json file from a serviceconfig.API and library information.
+func FromAPI(api *serviceconfig.API, library *config.Library, language, repo, defaultVersion, outputDir string) error {
 	clientDocURL := buildClientDocURL(language, extractNameFromAPIID(api.ServiceName))
-	metadata := &RepoMetadata{
-		APIID:               api.ServiceName,
-		NamePretty:          cleanTitle(api.Title),
-		DefaultVersion:      defaultVersion,
-		ClientDocumentation: clientDocURL,
-		ReleaseLevel:        info.ReleaseLevel,
-		Language:            language,
-		LibraryType:         "GAPIC_AUTO",
-		Repo:                repo,
-		DistributionName:    info.Name,
+	apiDescription := api.Description
+	if library.DescriptionOverride != "" {
+		apiDescription = library.DescriptionOverride
 	}
-
-	metadata.ProductDocumentation = extractBaseProductURL(api.DocumentationURI)
-	metadata.IssueTracker = api.NewIssueURI
-	metadata.APIShortname = api.ShortName
-	metadata.Name = api.ShortName
-	metadata.APIDescription = api.Description
-	if info.DescriptionOverride != "" {
-		metadata.APIDescription = info.DescriptionOverride
+	metadata := &RepoMetadata{
+		APIDescription:       apiDescription,
+		APIID:                api.ServiceName,
+		APIShortname:         api.ShortName,
+		ClientDocumentation:  clientDocURL,
+		DefaultVersion:       defaultVersion,
+		DistributionName:     library.Name,
+		IssueTracker:         api.NewIssueURI,
+		Language:             language,
+		LibraryType:          "GAPIC_AUTO",
+		Name:                 api.ShortName,
+		NamePretty:           cleanTitle(api.Title),
+		ProductDocumentation: extractBaseProductURL(api.DocumentationURI),
+		ReleaseLevel:         library.ReleaseLevel,
+		Repo:                 repo,
 	}
 
 	data, err := json.MarshalIndent(metadata, "", "    ")